The present invention relates to a new silver halide developing agent for color photographs, a processing composition containing the developing agent, and a method for forming a color image with the processing composition. In particular, the present invention relates to a developing agent for color photographs suitable for rapid processing of color photographs and capable of achieving a desired gradation relating to a yellow image, a processing composition containing the developing agent, and a method for forming a color image with the processing composition.
As mini-labs for processing photosensitive materials within the shops and the amount of color negative films used in the field of news photos are increasing recently, the demand for completion of the development process in a shorter time to immediately provide the prints to the customers or to immediately place the photo in newspapers or the like is rapidly increasing. The demand for reduction of the processing time is becoming more and more eager in processing color negative films, since the time necessitated therefor is longer than that necessitated for processing color papers.
For the reduction of the time necessitated for the color development step among the processing steps, Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. Sho 61-261740 discloses a method for processing a color paper mainly comprising a silver chlorobromide emulsion, wherein an N-hydroxyalkyl-substituted p-phenylenediamine derivative is used as the color developing agent; and European Patent No. 410,450 discloses a method for processing a color paper mainly comprising a silver chloride emulsion, wherein a specified N-hydroxyalkyl-substituted p-phenylenediamine derivative is used as the color developing agent. Also, it is disclosed in J. P. KOKAI No. Hei 5-113635 that when 4-(N-ethyl-N-.delta.-hydroxybutylamino)-2-methylaniline is used in place of ordinarily used 4-(N-ethyl-N-.beta.-hydroxyethylamino)-2-methylaniline in the development of a color photographic sensitive materials mainly comprising a silver bromoiodide emulsion such as color negative films, the sensitivity is unchanged even by reducing the color development time from 3 minute 15 seconds to 2 minute 30 seconds.
Thus the reduction in the processing time is also possible by changing the color developing agent in the color photographic photosensitive materials mainly comprising the silver bromoiodide emulsion such as the color negative films. It was found that the processing time can be remarkably reduced by even only introducing a methoxy group into 2-position to form 4-(N-ethyl-N-.delta.-hydroxybutylamino)-2-methylaniline as described in the above-described J. P. KOKAI No. Hei 5-113635 or 4-(N-ethyl-N-.beta.-hydroxyethylamino)-2-methoxyaniline as described in J.P. KOKAI No. 53-69035.
However, it was also found that although only magenta and cyan images can be rapidly formed with such a color developing agent, the contract of yellow images becomes seriously low and is practically useless. The problem of the low contrast could not be solved at all with a color developing agent having an alkoxy group at the 2-position such as 4-{N,N-bis(5-hydroxypentylamino)}-2-methoxyaniline described in British Patent No. 807,899, 4-{N,N-bis(5-hydroxypentylamino)}-2-ethoxyaniline described in the above-described J. P. KOKAI No. Hei 5-113635 or 4-(N-butyl-N-.beta.,.gamma.-dihydroxypropylamino)-2-methoxyaniline described in Journal fuer Signalaufzeichungsmaterialien Vol. 2, p. 277 (1974).
Although the color developing agents of the present invention include some of compounds generally set forth in the claim of the above-described British Patent No. 807,899, the specification of this patent has no specific description on the compounds corresponding to the color developing agents of the present invention and there is given no direct description or indirect description suggesting the possibility of reducing the time necessitated for the color developing step and preventing the low contrast of the yellow image at the same time.